Question

Darwin was most influenced by the research work of
(a) Wallace
(b) Spencer
(c) Malthus
(d) Weismann

Answer 1

Hint: The scientist by whose work Darwin was most influenced was a naturalist who worked in the Malay Archipelago and wrote “Essay on the Principle of Population”. The conclusions made by him in regard to evolution were similar to the conclusions that Darwin had reached.

Complete Answer:
Alfred Wallace is a scientist whose research work influenced Darwin the most. He came up with the theory of natural selection based on his work and entirely independent of Charles Darwin. This encouraged Darwin to collaborate with Wallace and they both combinedly came up with the theory of natural selection. This theory is also known as organic evolution.

Additional information: Let us understand in detail the theory of natural selection.
- Overproduction: First, the species produces an enormous number of offspring which contains variation.
- Variations: Then the extra population is eliminated because not all the offspring can survive because of population stress. Only the ones with variations best suited for their environment survive.
- The constancy of population size: the interspecific, intraspecific, extra specific struggle for existence ensures constancy of population.
- Natural selection: Lastly, natural selection operates for the survival of the fittest. Then small changes occur from the parent generation to the next progeny which acts as a raw material for a source of evolution. And nature selects useful or adaptive variation.
So, the correct option is ‘(a) Wallace’.

Note:
- Lamarck proposed the theory of acquired characters which was disproved by Weismann.
- Instead, Weismann proposed the theory of continuity of germplasm.
- This theory states that only those characters will be inherited which caused some change in the germplasm i.e. chromosomes of gametes.